New Delhi, Aug. 13 -- India's aviation regulator has issued a show-cause notice to IndiGo for using "non-qualified simulators" to train pilots operating to three challenging airports, citing scrutiny of records and email replies from the airline. The Directorate General of Civil Aviation notice, issued on Monday and seen by HT, found that "Category C (Critical) airfield training for flight crew" was conducted using simulators not approved for specific airports as required under Civil Aviation Rules. It found that about 1,700 IndiGo pilots received training on simulators that lacked the required approval to prepare them for flights to Leh, Kozhikode and Kathmandu. These destinations are classified as "critical" airports, meaning they present...